Methods and apparatus for washing objects produced by stereolithography

ABSTRACT

Method of making a three-dimensional object, comprising the steps of: (a) providing a carrier platform on which the three-dimensional object can be formed; (b) producing the three-dimensional object, (c) immersing the object in a wash liquid with the object remaining adhered to the carrier platform; (d) agitating (i) the object in said wash liquid, (ii) the wash liquid with the object immersed therein, or (iii) both the object and the wash liquid, to at least partially remove residual resin from the surface of the object; (e) separating the object from the wash liquid, with the object remaining adhered to the carrier platform, (f) agitating the object to at least partially remove residual wash liquid from the surface thereof; and (g) repeating steps (c) through (f) to remove additional polymerizable resin from the surface thereof, wherein steps (c) through (f) are carried out in the same vessel.

RELATED APPLICATIONS

This application claims the benefit of U.S. provisional patentapplication Ser. No. 62/434,043, filed Dec. 14, 2016, and U.S.provisional patent application Ser. No. 62/471,094, filed Mar. 14, 2017,the disclosures of which are incorporated by reference herein in theirentireties.

FIELD OF THE INVENTION

The present invention concerns additive manufacturing, and particularlyconcerns methods, apparatus, and systems for washing objects made byadditive manufacturing.

BACKGROUND OF THE INVENTION

The production of three-dimensional objects from polymerizable resins bystereolithography has been known for some time (see, e.g., U.S. Pat. No.5,236,637 to Hull). Unfortunately, such techniques have been generallyconsidered slow, and are typically limited to resins that producebrittle or fragile objects suitable only as prototypes. A more recenttechnique known as continuous liquid interface production (CLIP) allowsmore rapid production of objects by stereolithography (see, e.g., U.S.Pat. No. 9,205,601 to DeSimone et al.), and the recent introduction of avariety of different dual cure resins for stereolithography(particularly CLIP) makes possible the production of a much greatervariety of functional, useful objects with diverse material properties(see, e.g., U.S. Pat. No. 9,453,142 to Rolland et al.). Together, thesedevelopments open the door to the stereolithographic production of alarger number of objects with more diverse properties.

Objects produced by stereolithography are typically coated with viscousresidual resin, which must be cleaned from the surface thereof beforeuse. While numerous methods and apparatus for cleaning such objects areknown (see, e.g., U.S. Pat. Nos. 5,248,456; 5,482,659, 6,660,208;6,996,245; and 8,529,703), they are not adapted to cleaning largernumbers of more diverse parts having much more diverse materialproperties. Accordingly, there is a need for new methods and apparatusfor washing objects produced by stereolithography.

SUMMARY OF THE INVENTION

A first aspect of the invention is a method of making athree-dimensional object from a polymerizable resin. The method includesthe steps of: (a) providing a carrier platform on which thethree-dimensional object can be formed; (b) producing thethree-dimensional object adhered to the carrier platform from thepolymerizable resin by stereolithography, the object having residualresin on the surface thereof; (c) immersing the object in a wash liquidwith the object remaining adhered to the carrier platform; (d)agitating: (i) the object in the wash liquid (e.g., by spinning), (ii)the wash liquid with the object immersed therein (e.g., by sonication ofthe wash liquid), or (iii) both the object in the wash liquid and thewash liquid with the object immersed therein, to at least partiallyremove residual resin from the surface of the object; (e) separating theobject from the wash liquid (for example, by draining the wash liquid),with the object remaining adhered to the carrier platform, the objecthaving residual wash liquid on the surface thereof; agitating the object(e.g., by spinning, optionally but preferably at a more rapid speed thanthe spinning of step (d)) to at least partially remove residual washliquid from the surface thereof; and (g) repeating steps (c) through atleast once to remove additional polymerizable resin from the surfacethereof, wherein steps (c) through U) are carried out in the samevessel, the immersing step (c) comprises filling the vessel with thewash liquid, and the separating step (e) comprises draining the washliquid from the vessel.

A further aspect of the invention is a method of making athree-dimensional object from a polymerizable resin, which is similar tothe foregoing, but different in some respects. This method includes thesteps of: (a) providing a carrier platform on which thethree-dimensional object can be formed; (b) producing thethree-dimensional object adhered to the carrier platform from thepolymerizable resin by stereolithography, the object having residualresin on the surface thereof; and also generating wash cycle parameters,and optionally also dry cycle parameters (for example, by selecting washand optionally dry cycle parameters, such as from a plurality ofpredetermined distinct wash, and optionally dry, cycle parameters), forthe object in the wash liquid, wherein at least one parameter of thewash cycle, and the dry cycle when present, is modified (for example, ascompared to the parameters of other members of a set of distinct wash,and optionally dry cycle parameters, e.g., gentle, moderate, andvigorous) based on (i) at least one characteristic of the objectconfiguration, (ii) at least one characteristic of the polymerizableresin, (iii) the orientation of the object on the carrier platform, or(iv) a combination thereof; (c) immersing the object in a wash liquidwith the object remaining adhered to the carrier platform; (d)agitating, according to the wash cycle parameters, (i) the object in thewash liquid (e.g., by spinning the object), (ii) the wash liquid withthe object immersed therein (e.g., by sonication of the wash liquid), or(iii) both the object in the wash liquid and the wash liquid with theobject immersed therein, to at least partially remove residual resinfrom the surface of the object; (e) separating the object from the washliquid (for example, by draining the wash liquid), with the objectremaining adhered to the carrier platform, the object having residualwash liquid on the surface thereof; (f) optionally agitating (e.g., byspinning, optionally but preferably at a more rapid speed than thespinning of step (d)), according to the dry cycle parameters, the objectto at least partially remove residual wash liquid from the surfacethereof; and (g) optionally repeating steps (c) through (f) at leastonce to remove additional polymerizable resin from the surface thereof(for example, with the optionally repeating step determined incombination with, or in accordance with, the step of generating orselecting wash, and optionally dry, cycle parameters).

A further aspect of the invention is an apparatus useful for washingresidual resin from the surface of an object produced bystereolithography, which object is adhered to a carrier platform. Theapparatus includes: (a) a wash vessel configured to receive the objectadhered to the carrier platform; (b) a reservoir positioned below thewash vessel and configured to contain at least sufficient wash liquid tofill the wash vessel; (c) a drain line connecting the wash vessel to thereservoir, the drain line optionally having a valve operativelyassociated therewith; (d) optionally, a fill line connecting thereservoir to the wash vessel, the fill line having a pump operativelyassociated therewith; (e) an object agitator on which the carrierplatform can be mounted, the object agitator having an agitator driveoperatively associated therewith; and (f) an elevator operativelyassociated with the agitator and configured to lower the carrierplatform into the wash vessel, the elevator having an elevator driveoperatively associated therewith.

A further aspect of the invention is an additive manufacturing system.The system includes: (a) a carrier platform on which an object may beproduced by stereolithography, the carrier platform including a uniqueidentifier thereon; (b) a stereolithography apparatus, the apparatusconfigured to releasably secure the carrier platform for producing anobject thereon, the apparatus including a unique identifier reader; (c)a wash apparatus (e.g., an apparatus as described herein), the washapparatus configured to releasably secure the carrier platform forwashing an object produced thereon, the wash apparatus including aunique identifier reader. In some embodiments, the system is configuredto execute a plurality of different wash cycles or programs (e.g., amethod as described herein). In some embodiments, the system includes(d) a memory operatively associated with the stereolithography apparatusand the wash apparatus and configured to store object information fromthe stereolithography apparatus from which a wash cycle in the washapparatus is selected.

Further aspects of the present invention are explained in greater detailin the drawings herein and the specification below. The disclosures ofall United States Patent references cited herein are to be incorporatedherein by reference in their entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a method of the present inventionemploying both wash and dry (or drain) cycles, with the object remainingon the carrier platform on which it was stereolithographically produced.

FIG. 2 illustrates a system of the invention comprising an additivemanufacturing machine and a washer.

FIG. 3A schematically illustrates a first embodiment of wash and drycycles of the present invention.

FIG. 3B schematically illustrates a second embodiment of wash and drycycles of the present invention.

FIG. 4 schematically illustrates a first embodiment of an apparatus ofthe present invention.

FIG. 5 schematically illustrates a second embodiment of a wash apparatusof the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present invention is now described more fully hereinafter withreference to the accompanying drawings, in which embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein; rather these embodiments are provided sothat this disclosure will be thorough and complete and will fully conveythe scope of the invention to those skilled in the art.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises” or“comprising,” when used in this specification, specify the presence ofstated features, integers, steps, operations, elements components and/orgroups or combinations thereof, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components and/or groups or combinations thereof.

As used herein, the term “and/or” includes any and all possiblecombinations or one or more of the associated listed items, as well asthe lack of combinations when interpreted in the alternative (“or”).

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly-useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the specification andclaims and should not be interpreted in an idealized or overly formalsense unless expressly so defined herein. Well-known functions orconstructions may not be described in detail for brevity and/or clarity.

It will be understood that when an element is referred to as being “on,”“attached” to, “connected” to, “coupled” with, “contacting,” etc.,another element, it can be directly on, attached to, connected to,coupled with and/or contacting the other element or intervening elementscan also be present. In contrast, when an element is referred to asbeing, for example, “directly on,” “directly attached” to, “directlyconnected” to, “directly coupled” with or “directly contacting” anotherelement, there are no intervening elements present. It will also beappreciated by those of skill in the art that references to a structureor feature that is disposed “adjacent” another feature can have portionsthat overlap or underlie the adjacent feature.

Spatially relative terms, such as “under,” “below,” “lower,” “over,”“upper” and the like, may be used herein for ease of description todescribe an element's or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is inverted, elements described as “under” or “beneath” otherelements or features would then be oriented “over” the other elements orfeatures. Thus the exemplary term “under” can encompass both anorientation of over and under. The device may otherwise be oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Similarly, the terms“upwardly,” “downwardly,” “vertical,” “horizontal” and the like are usedherein for the purpose of explanation only, unless specificallyindicated otherwise.

It will be understood that, although the terms first, second, etc., maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. Rather, these terms areonly used to distinguish one element, component, region, layer and/orsection, from another element, component, region, layer and/or section.Thus, a first element, component, region, layer or section discussedherein could be termed a second element, component, region, layer orsection without departing from the teachings of the present invention.The sequence of operations (or steps) is not limited to the orderpresented in the claims or figures unless specifically indicatedotherwise.

“Unique identifier” and “identifier reader” as used herein refer tocomponents of an automatic identification and data capture system.Suitable unique identifiers include, but are not limited to, bar codes(including one-dimensional and two-dimensional bar codes), near fieldcommunication (NFC) tags, radio frequency identification (RFID) tags(including active, passive, and battery-assisted passive RFID tags),optical character recognition (OCR) tags and readers, magnetic stripsand readers, etc.

1. Production of Objects for Washing.

The three-dimensional intermediate to be washed is preferably formedfrom polymerizable resins by additive manufacturing, typically bottom-upor top-down additive manufacturing, generally known asstereolithography. Such methods are known and described in, for example,U.S. Pat. No. 5,236,637 to Hull, U.S. Pat. Nos. 5,391,072 and 5,529,473to Lawton, U.S. Pat. No. 7,438,846 to John, U.S. Pat. No. 7,892,474 toShkolnik, U.S. Pat. No. 8,110,135 to El-Siblani, US Patent ApplicationPublication No. 2013/0292862 to Joyce, and US Patent ApplicationPublication No. 2013/0295212 to Chen et al. The disclosures of thesepatents and applications are incorporated by reference herein in theirentirety.

In general, top-down three-dimensional fabrication is carried out by:

(a) providing a polymerizable liquid reservoir having a polymerizableliquid fill level and a carrier positioned in the reservoir, the carrierand the fill level defining a build region therebetween;

(b) filling the build region with a polymerizable liquid (i.e., theresin), said polymerizable liquid comprising a mixture of (i) a light(typically ultraviolet light) polymerizable liquid first component, and(ii) a second solidifiable component of the dual cure system; and then

(c) irradiating the build region with light to form a solid polymerscaffold from the first component and also advancing (typicallylowering) the carrier away from the build surface to form athree-dimensional intermediate having the same shape as, or a shape tobe imparted to, the three-dimensional object and containing said secondsolidifiable component (e.g., a second reactive component) carried inthe scaffold in unsolidified and/or uncured form.

A wiper blade, doctor blade, or optically transparent (rigid orflexible) window, may optionally be provided at the fill level tofacilitate leveling of the polymerizable liquid, in accordance withknown techniques. In the case of an optically transparent window, thewindow provides a build surface against which the three-dimensionalintermediate is formed, analogous to the build surface in bottom-upthree-dimensional fabrication as discussed below.

In general, bottom-up three-dimensional fabrication is carried out by:

(a) providing a carrier and an optically transparent member having abuild surface, the carrier and the build surface defining a build regiontherebetween;

(b) filling the build region with a polymerizable liquid (i.e., theresin), said polymerizable liquid comprising a mixture of (i) a light(typically ultraviolet light) polymerizable liquid first component, and(ii) a second solidifiable component of the dual cure system; and then

(c) irradiating the build region with light through said opticallytransparent member to form a solid polymer scaffold from the firstcomponent and also advancing (typically raising) the carrier away fromthe build surface to form a three-dimensional intermediate having thesame shape as, or a shape to be imparted to, the three-dimensionalobject and containing said second solidifiable component (e.g., a secondreactive component) carried in the scaffold in unsolidified and/oruncured form.

In some embodiments of bottom-up or top-down three-dimensionalfabrication as implemented in the context of the present invention, thebuild surface is stationary during the formation of thethree-dimensional intermediate; in other embodiments of bottom-upthree-dimensional fabrication as implemented in the context of thepresent invention, the build surface is tilted, slid, flexed and/orpeeled, and/or otherwise translocated or released from the growingthree-dimensional intermediate, usually repeatedly, during formation ofthe three-dimensional intermediate.

In some embodiments of bottom-up or top-down three-dimensionalfabrication as carried out in the context of the present invention, thepolymerizable liquid (or resin) is maintained in liquid contact withboth the growing three dimensional intermediate and the build surfaceduring both the filling and irradiating steps, during fabrication ofsome of, a major portion of, or all of the three-dimensionalintermediate.

In some embodiments of bottom-up or top-down three-dimensionalfabrication as carried out in the context of the present invention, thegrowing three-dimensional intermediate is fabricated in a layerlessmanner (e.g., through multiple exposures or “slices” of patternedactinic radiation or light) during at least a portion of the formationof the three-dimensional intermediate.

In some embodiments of bottom-up or top-down three-dimensionalfabrication as carried out in the context of the present invention, thegrowing three-dimensional intermediate is fabricated in a layer-by-layermanner (e.g., through multiple exposures or “slices” of patternedactinic radiation or light), during at least a portion of the formationof the three-dimensional intermediate.

In some embodiments of bottom-up or top-down three-dimensionalfabrication employing a rigid or flexible optically transparent window,a lubricant or immiscible liquid may be provided between the window andthe polymerizable liquid (e.g., a fluorinated fluid or oil such as aperfluoropolyether oil).

From the foregoing it will be appreciated that, in some embodiments ofbottom-up or top-down three-dimensional fabrication as carried out inthe context of the present invention, the growing three-dimensionalintermediate is fabricated in a layerless manner during the formation ofat least one portion thereof, and that same growing three-dimensionalintermediate is fabricated in a layer-by-layer manner during theformation of at least one other portion thereof. Thus, operating modemay be changed once, or on multiple occasions, between layerlessfabrication and layer-by-layer fabrication, as desired by operatingconditions such as part geometry.

In some embodiments, the intermediate is formed by continuous liquidinterface production (CLIP). CLIP is known and described in, forexample, PCT Application Nos. PCT/US2014/015486 (published as U.S. Pat.No. 9,211,678 on Dec. 15, 2015); PCT/US2014/015506 (also published asU.S. Pat. No. 9,205,601 on Dec. 8, 2015), PCT/US2014/015497 (alsopublished as U.S. Pat. No. 9,216,546 on Dec. 22, 2015), and in J.Tumbleston, D. Shirvanyants, N. Ermoshkin et al., Continuous liquidinterface production of 3D Objects, Science 347, 1349-1352 (publishedonline 16 Mar. 2015). See also R. Janusziewcz et al., Layerlessfabrication with continuous liquid interface production, Proc. Natl.Acad. Sci. USA 113, 11703-11708 (Oct. 18, 2016). In some embodiments,CLIP employs features of a bottom-up three-dimensional fabrication asdescribed above, but the the irradiating and/or said advancing steps arecarried out while also concurrently maintaining a stable or persistentliquid interface between the growing object and the build surface orwindow, such as by: (i) continuously maintaining a dead zone ofpolymerizable liquid in contact with said build surface, and (ii)continuously maintaining a gradient of polymerization zone (such as anactive surface) between the dead zone and the solid polymer and incontact with each thereof, the gradient of polymerization zonecomprising the first component in partially cured form. In someembodiments of CLIP, the optically transparent member comprises asemipermeable member (e.g., a fluoropolymer), and the continuouslymaintaining a dead zone is carried out by feeding an inhibitor ofpolymerization through the optically transparent member, therebycreating a gradient of inhibitor in the dead zone and optionally in atleast a portion of the gradient of polymerization zone. Other approachesfor carrying out CLIP that can be used in the present invention andpotentially obviate the need for a semipermeable “window” or windowstructure include utilizing a liquid interface comprising an immiscibleliquid (see L. Robeson et al., WO 2015/164234, published Oct. 29, 2015),generating oxygen as an inhibitor by electrolysis (see I. Craven et al.,WO 2016/133759, published Aug. 25, 2016), and incorporating magneticallypositionable particles to which the photoactivator is coupled into thepolymerizable liquid (see J. Rolland, WO 2016/145182, published Sep. 15,2016).

In some embodiments, the intermediate object is formed from a dual curestereolithography resin. Such resins are described in, for example, J.Rolland et al., PCT Applications PCT/US2015/036893 (see also US PatentApplication Pub. No. US 2016/0136889), PCT/US2015/036902 (see also USPatent Application Pub. No. US 2016/0137838), PCT/US2015/036924 (seealso US Patent Application Pub. No. US 2016/016077), andPCT/US2015/036946 (see also U.S. Pat. No. 9,453,142).

Particular examples of suitable resins include, but are not limited to,Carbon, Inc. rigid polyurethane resin (RPU), flexible polyurethane resin(FPU), elastomeric polyurethane resin (EPU), cyanate ester resin (CE),epoxy resin (EPX), or urethane methacrylate resin (UMA), all availablefrom Carbon, Inc., 1089 Mills Way, Redwood City, Calif. 94063 USA.

In general, objects formed by resins as described above have residual,unpolymerized or partially polymerized, resin on the surface thereof,which must be cleaned or washed from the object, as described furtherbelow.

2. Wash Liquids.

Wash liquids that may be used to carry out the present inventioninclude, but are not limited to, water, organic solvents, andcombinations thereof (e.g., combined as co-solvents), optionallycontaining additional ingredients such as surfactants, chelants(ligands), enzymes, borax, dyes or colorants, fragrances, etc.,including combinations thereof. The wash liquid may be in any suitableform, such as a solution, emulsion, dispersion, etc.

In some preferred embodiments, where the residual resin has a boilingpoint of at least 90 or 100° C. (e.g., up to 250 or 300° C., or more),the wash liquid has a boiling point of at least 30° C., but not morethan 80 or 90° C. Boiling points are given herein for a pressure of 1bar or 1 atmosphere.

Examples of organic solvents that may be used as a wash liquid, or as aconstituent of a wash liquid, include, but are not limited to, alcohol,ester, dibasic ester, ketone, acid, aromatic, hydrocarbon, ether,dipolar aprotic, halogenated, and base organic solvents, includingcombinations thereof. Solvents may be selected based, in part, on theirenvironmental and health impact (see, e.g., GSK Solvent Selection Guide2009).

Examples of alcohol organic solvents that may be used in the presentinvention include, but are not limited to, aliphatic and aromaticalcohols such as 2-ethyl hexanol, glycerol, cyclohexanol, ethyleneglycol, propylene glycol, di-propylene glycol, 1,4-butanediol, isoamylalcohol, 1,2-propanediol, 1,3-propanediol, benzyl alcohol, 2-pentanol,1-butanol, 2-butanol, methanol, ethanol, t-butanol, 2-propanol,1-propanol, 2-methoxyethanol, tetrahydrofuryl alcohol, benzyl alcohol,etc., including combinations thereof. In some embodiments, a C1-C6 orC1-C4 aliphatic alcohol is preferred.

Examples of ester organic solvents that may be used to carry out thepresent invention include, but are not limited to, t-butyl acetate,n-octyl acetate, butyl acetate, ethylene carbonate, propylene carbonate,butylenes carbonate, glycerol carbonate, isopropyl acetate, ethyllactate, propyl acetate, dimethyl carbonate, methyl lactate, ethylacetate, ethyl propionate, methyl acetate, ethyl formate etc., includingcombinations thereof.

Examples of dibasic ester organic solvents include, but are not limitedto, dimethyl esters of succinic acid, glutaric acid, adipic acid, etc.,including combinations thereof.

Examples of ketone organic solvents that may be used to carry out thepresent invention include, but are not limited to, cyclohexanone,cyclopentanone, 2-pentanone, 3-pentanone, methylisobutyl ketone,acetone, methylethyl ketone, etc., including combinations thereof.

Examples of acid organic solvents that may be used to carry out thepresent invention include, but are not limited to, propionic acid,acetic anhydride, acetic acid, etc., including combinations thereof.Examples of aromatic organic solvents that may be used to carry out thepresent invention include, but are not limited to, mesitylene, cumene,p-xylene, toluene, benzene, etc., including combinations thereof.

Examples of hydrocarbon (i.e., aliphatic) organic solvents that may beused to carry out the present invention include, but are not limited to,cis-decalin, ISOPAR G, isooctane, methyl cyclohexane, cyclohexane,heptane, pentane, methylcyclopentane, 2-methylpentane, hexane, petroleumspirit, etc., including combinations thereof.

Examples of ether organic solvents that may be used to carry out thepresent invention include, but are not limited to, di(ethylene glycol),ethoxybenzene, tri(ethylene glycol), sulfolane, DEG monobutyl ether,anisole, diphenyl ether, dibutyl ether, t-amyl methyl ether,t-butylmethyl ether, cyclopentyl methyl ether, t-butyl ethyl ether,2-methyltetrahydrofuran, diethyl ether, bis(2-methoxyethyl) ether,dimethyl ether, 1,4-dioxane, tetrahydrofuran, 1,2-dimethoxyethane,diisopropyl ether, etc., including combinations thereof.

Examples of dipolar aprotic organic solvents that may be used to carryout the present invention include, but are not limited to,dimethylpropylene urea, dimethyl sulphoxide, formamide, dimethylformamide, N-methylformamide, N-methyl pyrrolidone, propanenitrile,dimethyl acetamide, acetonitrile, etc., including combinations thereof.

Examples of halogenated organic solvents that may be used to carry outthe present invention include, but are not limited to,1,2-dichlorobenzene, 1,2,4-trichlorobenzene, chlorobenzene,trichloroacetonitrile, chloroacetic acid, trichloroacetic acid,perfluorotoluene, perfluorocyclohexane, carbon tetrachloride,dichloromethane, perfluorohexane, fluorobenzene, chloroform,perfluorocyclic ether, trifluoracetic acid, trifluorotoluene,1,2-dichloroethane, 2,2,2-trifluoroethanol, etc., including combinationsthereof.

Examples of base organic solvents that may be used to carry out thepresent invention include, but are not limited to, N,N-dimethylaniline,triethylamine, pyridine, etc., including combinations thereof.

Examples of other organic solvents that may be used to carry out thepresent invention include, but are not limited to, nitromethane, carbondisulfide, etc., including combinations thereof.

Examples of surfactants include, but are not limited to, anionicsurfactants (e.g., sulfates, sulfonates, carboxylates, and phosphateesters), cationic surfactants, zwitterionic surfactants, nonionicsurfactants, etc., including combinations thereof. Common examplesinclude, but are not limited to, sodium stearate, linearalkylbenzenesulfonates, lignin sulfonates, fatty alcohol ethoxylates,alkylphenol ethoxylates, etc., including combinations thereof. Numerousexamples additional examples of suitable surfactants are known, some ofwhich are described in U.S. Pat. Nos. 9,198,847, 9,175,248, 9,121,000,9,120,997, 9,095,787, 9,068,152, 9,023,782, and 8,765,108.

Examples of chelants (chelating agents) include, but are not limited to,ethylenediamine tetraacetic acid, phosphates, nitrilotriacetic acid(NTA), citrates, silicates, and polymers of acrylic and maleic acid.

Examples of enzymes that may be included in the wash liquid include, butare not limited to, proteases, amylases, lipases, cellulases, etc.,including mixtures thereof. See, e.g., U.S. Pat. Nos. 7,183,248,6,063,206.

In some embodiments, the wash liquid can be an aqueous solution ofethoxylated alcohol, sodium citrate, tetrasodiumN,N-bis(carboxymethyl)-L-glutamate, sodium carbonate, citric acid, andisothiazolinone mixture. One particular example thereof is SIMPLE GREEN®all purpose cleaner (Sunshine Makers Inc., Huntington Beach, Calif.,USA), used per se or mixed with additional water.

In some embodiments, the wash liquid can be an aqueous solutioncomprised of of 2-butoxyethanol, sodium metasilicate, and sodiumhydroxide. One particular example thereof is PURPLE POWER™degreaser/cleaner (Aiken Chemical Co., Greenville, S.C., USA), used perse or mixed with additional water.

In some embodiments, the wash liquid can be ethyl lactate, alone or witha co-solvent. One particular example thereof is BIO-SOLV™ solventreplacement (Bio Brands LLC, Cinnaminson, N.J., USA), used per se ormixed with water.

In some embodiments, the wash liquid consists of a 50:50 (volume:volume)solution of water and an alcohol organic solvent such as isopropanol(2-propanol).

Examples of hydrofluorocarbon solvents that may be used to carry out thepresent invention include, but are not limited to,1,1,1,2,3,4,4,5,5,5-decafluoropentane (Vertrel® XF, DuPont™ Chemours),1,1,1,3,3-Pentafluoropropane, 1,1,1,3,3-Pentafluorobutane, etc.

Examples of hydrochlorofluorocarbon solvents that may be used to carryout the present invention include, but are not limited to,3,3-Dichloro-1,1,1,2,2-pentafluoropropane,1,3-Dichloro-1,1,2,2,3-pentafluoropropane, 1,1-Dichloro-1-fluoroethane,etc., including mixtures thereof.

Examples of hydrofluorether solvents that may be used to carry out thepresent invention include, but are not limited to, methylnonafluorobutyl ether (HFE-7100), methyl nonafluoroisobutyl ether(HFE-7100), ethyl nonafluorobutyl ether (HFE-7200), ethylnonafluoroisobutyl ether (HFE-7200),1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, etc., includingmixtures thereof. Commercially available examples of this solventinclude Novec 7100 (3M), Novec 7200 (3M).

Examples of volatile methylsiloxane solvents that may be used to carryout the present invention include, but are not limited to,hexamethyldisiloxane (OS-10, Dow Corning), octamethyltrisiloxane (OS-20,Dow Corning), decamethyltetrasiloxane (OS-30, Dow Corning), etc.,including mixtures thereof.

Other siloxane solvents (e.g., NAVSOLVE™ solvent) that may be used tocarry out the present invention include but are not limited to those setforth in U.S. Pat. No. 7,897,558.

In some embodiments, the wash liquid comprises an azeotropic mixturecomprising, consisting of, or consisting essentially of a first organicsolvent (e.g., a hydrofluorocarbon solvent, a hydrochlorofluorocarbonsolvent, a hydrofluorether solvent, a methylsiloxane solvent, or acombination thereof; e.g., in an amount of from 80 or 85 to 99 percentby weight) and a second organic solvent (e.g., a C1-C4 or C6 alcoholsuch as methanol, ethanol, isopropanol, tert-butanol, etc.; e.g., in anamount of from 1 to 15 or 20 percent by weight). Additional ingredientssuch as surfactants or chelants may optionally be included. In someembodiments, the azeotropic wash liquid may provide superior cleaningproperties, and/or enhanced recyclability, of the wash liquid.Additional examples of suitable azeotropic wash liquids include, but arenot limited to, those set forth in U.S. Pat. Nos. 6,008,179; 6,426,327;6,753,304; 6,288,018; 6,646,020; 6,699,829; 5,824,634; 5,196,137;6,689,734; and 5,773,403, the disclosures of which are incorporated byreference herein in their entirety.

When the wash liquid includes ingredients that are not desired forcarrying into the further curing step, in some embodiments the initialwash with the wash liquid can be followed with a further rinsing stepwith a rinse liquid, such as water (e.g., distilled and/or deionizedwater), or a mixture of water and an alcohol such as isopropanol.

3. Methods and Apparatus.

Methods of carrying out the present invention are schematicallyillustrated in FIGS. 1, 2, 3A, and 3B. Non-limiting example of apparatususeful for carrying out the methods described herein are schematicallyillustrated in FIGS. 4-5. The apparatus generally includes: (a) a washvessel configured to receive the object adhered to the carrier platform;(b) a reservoir positioned below the wash vessel and configured tocontain at least sufficient wash liquid to fill the wash vessel; (c) adrain line connecting the wash vessel to the reservoir, the drain lineoptionally but preferably having a valve operatively associatedtherewith; (d) optionally, a fill line connecting the reservoir to thewash vessel, the fill line having a pump operatively associatedtherewith; (e) an object agitator (e.g., a rotor) on which the carrierplatform can be mounted, the object agitator having an agitator driveoperatively associated therewith; an elevator operatively associatedwith the agitator and configured to lower the carrier platform into thewash vessel, the elevator having an elevator drive operativelyassociated therewith; and (g) a controller operatively associated withthe valve, the pump, the agitator drive, and the elevator drive.

The apparatus of FIG. 5 differs from that of FIG. 4 in that it utilizesa pneumatic refill system (e.g., an air compressor and/or a compressedair vessel, or other source of compressed gas, operatively associatedwith a valve), rather than a separate pump and fill line for refillingthe wash vessel. In the apparatus of FIG. 5, note that the drain line isconfigured (e.g., by extending down close to the bottom of thereservoir) to fill the wash vessel with wash liquid through the drainline when the pneumatic pressure supply is activated. In this case, thedrain valve may be optional (as pneumatic pressure in the reservoir maybe sufficient to hold the wash liquid in the wash vessel), although insome embodiments inclusion of a drain valve is still preferred.Compressed air is currently preferred as the compressed gas. Once thewash vessel is re-filled, the drain valve may be closed, and compressedgas vented (typically through a commercial exhaust system) by opening anexhaust valve. For the next drain step, the exhaust valve may be leftopen, so that increasing pressure within the reservoir as it fills withwash liquid vessel does not slow the draining step.

With either the configuration of FIG. 4 or FIG. 5, pumps, valves,pneumatic pressure actuators, and the like can be configured, takinginto account the volume of wash liquid to be transferred, so thatwashing is rapid: For example, so that steps (c) through (f) asdescribed above and below (examples illustrated in FIG. 3A-B) arecarried out in a total time of not more than 1, 2, 5 or 10 minutes.

In some embodiments, the apparatus includes an identifier reader (e.g.,an NFC tag reader, an RFID tag reader or a bar code reader) operativelyassociated with the controller, and configured to receive informationfrom each object to be washed as identified by a unique identifierassociated with each carrier platform to which each object is adhered.In this case a unique identifier reader may also be included on thestereolithography apparatus, so that information on the object made canbe stored into memory and transferred to an associated wash apparatusupon recognition of the platform on which the object was made by a washapparatus (e.g., through a local network or a cloud-based system, suchas illustrated in FIG. 2). Controllers (e.g., software running on ageneral purpose computer, with appropriate interfaces) may be physicallylocated on either or both machines, on a separate control station, or acombination thereof.

In some embodiments, the controller includes a usage monitor configuredto accumulate wash liquid contamination data based on a plurality ofobjects washed separately in the wash liquid, as each member of theplurality is identified by each unique identifier associated with eachcarrier platform on which each object is adhered. For example, the usagemonitor may simply count the number of times a wash cycle has beenimplemented with a particular batch of wash liquid, may includeinformation on the particular resin or polymerizable liquid from whicheach part was made (for example, adjusting the number of permitted washcycles downwards when use of a resin particularly prone to soiling thewash liquid is used), adjust the number of permitted wash cycles basedon information transferred to memory about the particular object(s)being made and washed (for example, adjusting the number of permittedwash cycles downwards when large or high surface-area parts areproduced), etc. The usage monitor may be operatively associated with adisplay indicating remaining numbers of washes available before the washliquid should be changed, a warning light and/or sound, a lock-outmechanism (whereby the washing machine becomes inoperable if the washliquid is not changed), etc., including combinations thereof.

In some embodiments, the controller includes a wash cycle parametergenerator configured to generate a wash cycle for an object based ondata for that object, as that object is identified by the uniqueidentifier associated with the carrier platform on which that object isadhered (see further discussion below).

In some embodiments, the apparatus further includes a liquid agitator(e.g., a sonicator) operatively associated with the wash vessel and thecontroller. This may be selectively activated (alone or in combinationwith other forms of agitation such as spinning) to provide a more gentleform of agitation when required for particular part geometries, or whereparts may include deep cavities that might not otherwise be reached by aspinning form of agitation.

In some embodiments, the apparatus further includes a fill sensoroperatively associated with the wash vessel and the controller.

In some embodiments, the apparatus further includes a docking lineconnected to the reservoir, the docking line having a docking valveoperatively associated therewith, the docking valve also operativelyassociated with the controller; and/or a distillation apparatusoperatively connected to the reservoir, optionally with the distillationapparatus operatively connected to the controller.

As noted above, an aspect of the invention is a method of making athree-dimensional object from a polymerizable resin. The method includesthe steps of:

-   -   (a) providing a carrier platform on which the three-dimensional        object can be formed;    -   (b) producing the three-dimensional object adhered to the        carrier platform from the polymerizable resin by        stereolithography, the object having residual resin on the        surface thereof;    -   (c) immersing the object in a wash liquid with the object        remaining adhered to the carrier platform;    -   (d) agitating (i) the object in the wash liquid (e.g., by        spinning), (ii) the wash liquid with the object immersed therein        (e.g., by sonication of the wash liquid), or (iii) both the        object in the wash liquid and the wash liquid with the object        immersed therein, to at least partially remove residual resin        from the surface of the object;    -   (e) separating the object from the wash liquid, with the object        remaining adhered to the carrier platform, the object having        residual wash liquid on the surface thereof;    -   (f) agitating the object (e.g., by spinning) to at least        partially remove residual wash liquid from the surface thereof;        and    -   (g) repeating steps (c) through (f) at least once to remove        additional polymerizable resin from the surface thereof, wherein        steps (c) through 0 are carried out in the same vessel, the        immersing step (c) comprises filling the vessel with the wash        liquid, and the separating step (e) comprises draining the wash        liquid from the vessel.

As also noted above, a further aspect of the invention is a method ofmaking a three-dimensional object from a polymerizable resin, which issimilar to the foregoing, but different in some respects. The methodincludes the steps of:

-   -   (a) providing a carrier platform on which the three-dimensional        object can be formed;    -   (b) producing the three-dimensional object adhered to the        carrier platform from the polymerizable resin by        stereolithography, the object having residual resin on the        surface thereof; and also    -   generating or selecting wash cycle parameters, and optionally        also dry cycle parameters, for the object in the wash liquid,        wherein at least one parameter of the wash cycle, and the dry        cycle when present, is modified or selected based on (i) at        least one characteristic of the object configuration, (ii) at        least one characteristic of the polymerizable resin, (iii) the        orientation of the object on the carrier platform, or (iv) a        combination thereof;    -   (c) immersing the object in a wash liquid with the object        remaining adhered to the carrier platform;    -   (d) agitating, according to the wash cycle parameters, (i) the        object in the wash liquid (e.g., by spinning the object), (ii)        the wash liquid with the object immersed therein (e.g., by        sonication of the wash liquid), or (iii) both the object in the        wash liquid and the wash liquid with the object immersed        therein, to at least partially remove residual resin from the        surface of the object;    -   (e) separating the object from the wash liquid, with the object        remaining adhered to the carrier platform, the object having        residual wash liquid on the surface thereof;    -   (f) optionally agitating (e.g., by spinning), according to the        dry cycle parameters, the object to at least partially remove        residual wash liquid from the surface thereof; and    -   (g) optionally repeating steps (c) through (t) at least once to        remove additional polymerizable resin from the surface thereof        (e.g., in accordance with the step of generating or selecting        wash cycle parameters, and optionally also dry cycle        parameters).

In some embodiments of both of the foregoing, steps (c) through (f) arecarried out in the same vessel, the immersing step (c) comprises fillingthe vessel with the wash liquid, and the separating step (e) comprisesdraining the wash liquid from the vessel.

In some embodiments of both of the foregoing, the agitating step (d) andthe (optionally) agitating step (f) are both carried out by spinning thecarrier platform with the object remaining adhered thereto.

In some embodiments of both of the foregoing, the wash cycle parameters,and the dry cycle parameters when present, include duration ofagitation, maximum speed of agitation, acceleration of agitation,deceleration of agitation, and direction of agitation.

For example: The wash apparatus controller may include overall washcycles (that is, including number of repeats) of different durations,and/or wherein steps (c) through (f) are repeated (e.g., once or twice)or not, with the decision on whether to repeat based on the type ofresin from which the object is made (objects made form hard-to-cleanresins being subjected to multiple, or longer, cleaning cycles). Thecontroller may include wash cycles with different speeds of rotation,where objects that are highly asymmetric (e.g., “off balance loads”) arerotated at a lower speed during the agitating steps, and/or whereultrasonic agitation is implemented. The controller may include cyclesin which spin agitation can be selectively imparted in differentdirections (e.g., clockwise or counter-clockwise), depending on whichdirection may be more dynamically stable, or impart greater turbulence,based on the shape of the part (with greater turbulence being preferredby structurally strong objects, but less preferred for delicateobjects). In one particular, non-limiting, example, the wash apparatusmay be configured to carry out: (1) a “gentle” overall wash cycle (or“wash program”), e.g., of two to four sequential cycles, with a topagitation speed of 10 revolutions per minute (RPMs) for each wash stepand 30 RPMs for each drain step, carried out over a total of five to tenminutes; (2) a “moderate” wash program, e.g., of two to four sequentialcycles, with a top agitation speed of 30 revolutions per minute (RPMs)for each wash step and 300 RPMs for each drain step, with all cyclescompleted in a total of five to ten minutes; and (3) a “vigorous” washprogram, e.g., of two to four sequential cycles, with a top agitationspeed of 100 revolutions per minute (RPMs) for each wash step and 1,000RPMs for each drain step, carried out over a total time of five to tenminutes. Additional options can be included, and the speeds above can bevaried. Indeed, numerous different wash programs will be readilyrecognized by those skilled in the art. Where the washer reads a uniqueidentifier for an object produced with a resin having a low pre-bake, or“green” strength, such as some cyanate ester or elastomeric polyurethaneresins, then the washer can be configured to select and carry out agentle wash program. Where the washer reads a unique identifier for anobject produced with a resin having a stronger green strength, such assome urethane methacrylate resins, then the washer can be configured toselect and carry out a vigorous wash program. Where the washer reads aunique identifier for a part that includes delicate or fragile features,and/or is highly asymmetric or off balance for a spin cycle, then thewasher can be configured to select and carry out a less vigorous washprogram than might otherwise be carried out. Note that assigning of aparticular wash program to a particular part can occur at any time, suchas when the part is formed, or when the part is planned (e.g., resinmatched to geometric configuration), and the generating step may simplyinvolve retrieving and executing that previously selected wash program.And, the wash program(s) can optionally be modified uniquely to eachpart's geometry, based on predictive programs and/or a database ofactual part washing experience.

In some embodiments of both of the foregoing, the object and the carrierplatform together have both a center of mass and an axis of rotation,and wherein the center of mass is either aligned with or offset from theaxis of rotation.

In some embodiments of both of the foregoing, the residual resin has aboiling point of at least 90 or 100° C. (e.g., up to 250 or 300° C., ormore), and the wash liquid has a boiling point of from 30° C. to 80 or90° C.

In some embodiments of both of the forgoing, the wash liquid comprisesan organic solvent (e.g., a halogenated organic solvent, such as afluorinated organic solvent, or a siloxane solvent).

In some embodiments of both of the foregoing, the organic solventcomprises an azeotropic mixture comprised of at least a first organicsolvent (e.g., a hydrofluorocarbon solvent, a hydrochlorofluorocarbonsolvent, a hydrofluorether solvent, a methylsiloxane solvent, orcombination thereof; e.g., in an amount of from 80 or 85 to 99 percentby weight) and a second organic solvent (e.g., a C1-C4 or C6 alcoholsuch as methanol, ethanol, isopropanol, tert-butanol, etc.; e.g., in anamount of from 1 to 15 or 20 percent by weight).

In some embodiments of both of the foregoing, the carrier platformcomprises a unique identifier (e.g., a bar code, NFC tag or RFID tag),and the generating step is carried out with information associated withthe unique identifier.

Transfer of the carrier platform from the addive manufacturing apparatusto the wash apparatus may be carried out manually, robotically, orcombinations thereof. Systems for robotic transfer can be implemented inaccordance with known techniques employed in robotic manufacturingsystems, or variations thereof that will be apparent to those skilled inthe art. See, e.g., U.S. Pat. Nos. 6,627,016; 6,694,224; 7,146,705;8,651,160; 8,668,423; and 9,351,569.

4. Recycling of Wash Liquid.

When the wash liquid has become sufficiently contaminated with residualresin to unduly interfere with the washing of new objects, then theapparatus may be docked to a distillation apparatus through the dockingport, the docking valve opened and the wash liquid drained into aseparation apparatus (e.g., a distillation apparatus), and the washliquid distilled to separate it from residual resin and generate cleanedwash liquid, and the cleaned wash liquid pumped back into the reservoir.Operations may be reversed with the wash liquid pumped from thereservoir and drained from the distillation apparatus back into thereservoir, the wash liquid may be pumped both ways, etc. Numerousconfigurations of a distillation apparatus can be used, including butnot limited to those described in U.S. Pat. No. 3,661,721 to Rodgers;U.S. Pat. No. 4,622,102 to Diebel; U.S. Pat. No. 4,734,167 to Goeldner;U.S. Pat. No. 5,951,825 to Land; U.S. Pat. No. 6,830,661 to Land; andvariations of the foregoing that will be apparent to those skilled inthe art.

In some embodiments, the distillation apparatus may comprise a vacuumdistillation apparatus. In some embodiments, the vacuum distillationapparatus further comprises or includes a heater to heat the wash liquidduring boiling thereof (albeit at a temperature less than the boilingpoint under atmospheric pressure). Vacuum distillation is known, and anysuitable vacuum distillation apparatus may be used. See, e.g., U.S. Pat.Nos. 1,717,002; 1,852,205; 2,210,927; 3,347,754; 5,955,135; 5,980,695;etc. For example, a solvent (or wash liquid) resistant pump can be usedto evacuate vapor from the solvent headspace. The solvent can then beremoved, passed over a chiller/heat exchanger, and into a closed vesselat ambient temperature and pressure. Heat can then be added to the stillto maintain a sufficiently high temperature to continue boiling thesolvent at the lower boiling point. Evaporative cooling may lower thetemperature of the boiling vessel and stop the evaporation process, soadding heat to the system may then be necessary.

By employing a vacuum distillation apparatus, the temperature to whichthe wash liquid is heated above room temperature may be reduced (e.g.,not more than 50, 40, 35, or 30 degrees Centigrade), thereby reducingthe degredation of residual resin or “bottoms” in the wash liquid topotentially undesirable breakdown products thereof (e.g., reduce theformation of methyl methacrylate/methyl acrylate degradation products).

As noted above, in some embodiments, the controller can include a usagemonitor configured to accumulate wash liquid contamination data. Whenthe distiller is integrated to the smart washer it can determine whenthe soil load of the resin has reached an appropriate level to requiredistillation. This mode can be activated by the control logic for thesmart washer.

Two (or more) separate “batches” of wash liquid may be kept available,with one stored in a secondary storage tank. In this way, when it istime for one wash liquid to be distilled, the soiled wash liquid can betransferred into the still for distillation, and an alternate batch ofwash liquid can be transferred into the wash apparatus for use incleaning objects, while the other batch of wash liquid is beingdistilled.

The foregoing is illustrative of the present invention, and is not to beconstrued as limiting thereof. The invention is defined by the followingclaims, with equivalents of the claims to be included therein.

1. A method of making a three-dimensional object from a polymerizableresin, said method comprising the steps of: (a) providing a carrierplatform on which said three-dimensional object can be formed; (b)producing said three-dimensional object adhered to said carrier platformfrom said polymerizable resin by stereolithography, said object havingresidual resin on the surface thereof; (c) immersing said object in awash liquid with said object remaining adhered to said carrier platform;(d) agitating (i) said object in said wash liquid, (ii) said wash liquidwith said object immersed therein, or (iii) both said object in saidwash liquid and said wash liquid with said object immersed therein, toat least partially remove residual resin from the surface of saidobject; (e) separating said object from said wash liquid, with saidobject remaining adhered to said carrier platform, said object havingresidual wash liquid on the surface thereof; (f) agitating said objectto at least partially remove residual wash liquid from the surfacethereof; and (g) repeating steps (c) through U) at least once to removeadditional polymerizable resin from the surface thereof, wherein steps(c) through (f) are carried out in the same vessel, said immersing step(c) comprises filling said vessel with said wash liquid, and saidseparating step (e) comprises draining said wash liquid from saidvessel.
 2. A method of making a three-dimensional object from apolymerizable resin, said method comprising the steps of: (a) providinga carrier platform on which said three-dimensional object can be formed;(b) producing said three-dimensional object adhered to said carrierplatform from said polymerizable resin by stereolithography, said objecthaving residual resin on the surface thereof; and also generating orselecting wash cycle parameters, and optionally also dry cycleparameters, for said object in wash liquid, wherein at least oneparameter of said wash cycle, and said dry cycle when present, ismodified or selected based on (i) at least one characteristic of saidobject configuration, (ii) at least one characteristic of saidpolymerizable resin, (iii) the orientation of said object on saidcarrier platform, or (iv) a combination thereof; (c) immersing saidobject in a wash liquid with said object remaining adhered to saidcarrier platform; (d) agitating, according to said wash cycleparameters, (i) said object in said wash liquid, (ii) said wash liquidwith said object immersed therein, or (iii) both said object in saidwash liquid and said wash liquid with said object immersed therein, toat least partially remove residual resin from the surface of saidobject; (e) separating said object from said wash liquid, with saidobject remaining adhered to said carrier platform, said object havingresidual wash liquid on the surface thereof; (f) optionally agitating,according to said dry cycle parameters, said object to at leastpartially remove residual wash liquid from the surface thereof; and (g)optionally repeating steps (c) through (f) at least once to removeadditional polymerizable resin from the surface thereof.
 3. The methodof claim 2, wherein said optionally agitating step (f) is included. 4.The method of claim 2, wherein said optionally repeating step (g) isincluded.
 5. The method of claim 2, wherein said steps (c) through (f)are carried out in a total time of not more than 1, 2, 5 or 10 minutes.6. The method of claim 2, wherein said wash cycle parameters, and saiddry cycle parameters when present, include duration of agitation,maximum speed of agitation, acceleration of agitation, deceleration ofagitation, direction of agitation, and/or number of repeatings (g). 7.The method of claim 2, wherein steps (c) through (f) are carried out inthe same vessel, said immersing step (c) comprises filling said vesselwith said wash liquid, and said separating step (e) comprises drainingsaid wash liquid from said vessel.
 8. The method of claim 2, whereinsaid agitating step (d) and said agitating step (f) (when present) areboth carried out by spinning said carrier platform with said objectremaining adhered thereto, optionally but preferably wherein said step(d) spinning maxium speed is slower than said step (f) spinning maximumspeed.
 9. The method of claim 2, wherein said object and said carrierplatform together have both a center of mass and an axis of rotation,and wherein said center of mass is either aligned with or offset fromsaid axis of rotation.
 10. The method of claim 2, wherein said residualresin has a boiling point of at least 90 or 100° C., and said washliquid has a boiling point of from 30° C. to 80 or 90° C.
 11. The methodof claim 2, wherein said wash liquid comprises an organic solvent. 12.The method of claim 11, wherein said organic solvent comprises anazeotropic mixture comprised of at least a first organic solvent and asecond organic solvent.
 13. The method of claims 2 to 12, wherein saidcarrier platform comprises a unique identifier, and said generating orselecting step is carried out with information associated with saidunique identifier.
 14. The method of claim 2, further comprising thestep of: (h) distilling said wash liquid to remove residual resintherefrom and produce a distilled wash liquid; and then (i) repeatingsteps (a) through (g) with said distilled wash liquid.
 15. An apparatususeful for washing residual resin from the surface of an object producedby stereolithography, which object is adhered to a carrier platform, theapparatus comprising: (a) a wash vessel configured to receive saidobject adhered to said carrier platform; (b) a reservoir positionedbelow said wash vessel and configured to contain at least sufficientwash liquid to fill said wash vessel; (c) a drain line connecting saidwash vessel to said reservoir, said drain line optionally having a valveoperatively associated therewith; (d) optionally, a fill line connectingsaid reservoir to said wash vessel, said fill line having a pumpoperatively associated therewith; (e) an object agitator on which saidcarrier platform can be mounted, said object agitator having an agitatordrive operatively associated therewith; and (f) an elevator operativelyassociated with said agitator and configured to lower said carrierplatform into said wash vessel, said elevator having an elevator driveoperatively associated therewith.
 16. The apparatus of claim 15, furthercomprising: (g) a controller operatively associated with said valve,said pump, said agitator drive, and said elevator drive.
 17. Theapparatus of claim 16, further comprising: (h) an identifier readeroperatively associated with said controller, and configured to receiveinformation from each object to be washed as identified by a uniqueidentifier associated with each carrier platform to which each object isadhered.
 18. The apparatus of claim 16, wherein said controller includesa usage monitor configured to accumulate wash liquid contamination databased a plurality of objects washed separately in the wash liquid, aseach member of said plurality is identified by each unique identifierassociated with each carrier platform on which each object is adhered.19. The apparatus of claim 17, wherein said controller includes a washcycle parameter generator configured to generate a wash cycle for anobject based on data for that object, as that object is identified bythe unique identifier associated with the carrier platform on which thatobject is adhered.
 20. The apparatus of claim 15, wherein said objectagitator comprises a rotor.
 21. The apparatus of claim 15, furthercomprising a liquid agitator operatively associated with said washvessel and optionally said controller.
 22. The apparatus of claim 15,further comprising a fill sensor operatively associated with said washvessel and optionally said controller.
 23. The apparatus of claim 16,further comprising: a docking line connected to said reservoir, saiddocking line having a docking valve operatively associated therewith,said docking valve also operatively associated with said controller;and/or a distillation apparatus operatively connected to said reservoir,optionally with said distillation apparatus operatively connected tosaid controller.
 24. The apparatus of claim 15, further comprising apneumatic pressure supply operatively associated with said reservoir,with said reservoir and said drain line configured to fill said washvessel with wash liquid through said drain line when said pneumaticpressure supply is activated.
 25. The apparatus of claim 24, furthercomprising an exhaust valve operatively associated with said reservoir,and optionally with said controller, said exhaust valve configured to beopen to the atmosphere during draining of wash liquid from said washvessel to said reservoir, and closed to the atmosphere during filling ofsaid wash vessel with wash liquid from said reservoir.
 26. An additivemanufacturing system, comprising: (a) a carrier platform on which anobject may be produced by stereolithography, said carrier platformincluding a unique identifier thereon; (b) a stereolithographyapparatus, said apparatus configured to releasably secure said carrierplatform for producing an object thereon, said apparatus including aunique identifier reader; (c) a wash apparatus, said wash apparatusconfigured to releasably secure said carrier platform for washing anobject produced thereon, said wash apparatus including a uniqueidentifier reader.
 27. The system of claim 26, wherein said system isconfigured to execute a plurality of different wash cycles or programs.28. The system of claim 26, further comprising: (d) a memory operativelyassociated with said stereolithography apparatus and said wash apparatusand configured to store object information from said stereolithographyapparatus from which a wash cycle in said wash apparatus is selected.